The invention concerns an apparatus, a method and a use of the apparatus for automatically twisting metal wires. The conveyor system includes a conveyor belt that includes a conveyor having cavities, rollers in some of the cavities and a positioning component. The metal shell has the insulator inserted and held therein such that a proximal part of the insulator is exposed from the metal shell. A movable mouth portion is connected to the main body portion. The circuit then adjusts the frequency of tunable oscillator 201 such that the frequency of the tunable oscillator is substantially equal to the resonant frequency of the resonator 205 and stores a data state necessary for the tunable oscillator 201 to generate a signal with this target frequency in the future.